Assessment of logging efficiency and development of allometric models for predicting stumpage volume of some commercial tree species in Ghana

Abstract

The need to develop instruments to capture the realistic stumpage volume and infl uence loggers to improve on their logging effi ciency has been a topic of interest in recent times. This study assessed the logging effi ciency in Ghana and developed allometric models to predict stumpage volume. A total of 135 trees from nine timber species were sampled from three logging sites during commercial logging operations. The average logging recovery for all sampled trees was about 75 %. The small-end diameter of the merchantable residues averaged between 31 cm and 60 cm while their length values varied from 3.0 m to 8.5 m. In general, species-specifi c models exhibited better predictive power than mixed-species models. Models that predicted total merchantable volume from the volume of the extracted logs had the best fi ts, with Furnival index values ranging from 0.590 to 1.727. Results of the models’ validation indicated that mixed species models could predict merchantable volume better for relatively small trees than for big trees with merchantable volume greater than 20 m3. Keywords: sustainable forest management, logging effi ciency, stumpage, allometric models